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| Marshall One Watt Series http://maplifiers.net/forum/viewtopic.php?f=7&t=3127 |
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| Author: | Unstrung [ Tue Oct 06, 2015 12:52 pm ] |
| Post subject: | Marshall One Watt Series |
Oh man, can't believe I missed these. They made a bunch of one Watt amps based on the classics. Gassing for the one watt JCM800. https://marshallamps.com/products/ampli ... tt-series/ |
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| Author: | Snaxocaster [ Wed Oct 07, 2015 1:16 am ] |
| Post subject: | Re: Marshall One Watt Series |
Yeah, these li'l guys have been out for a while. Tiny amps came up in conversation with my IRL musicianfriends the other day when I stumbled upon a couple old Marshall Lead 12s at a guitar store around here. Those, incidentally, are pretty damn nice, especially if you can snag one for the price of a half-decent pedal. I can see a 1w t00b Marshall being a useful tool, hells yes. 
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| Author: | Unstrung [ Thu Oct 08, 2015 11:52 pm ] |
| Post subject: | Re: Marshall One Watt Series |
Y'know I just did a google search for Lead 12 and found results from eight years ago where everyone said they're cheap and nasty. But then I went on youtube and saw very recent clips heralding it as a 60$ plexi. Funny how time can change perspectives... I wonder if someday people will look back at Marshall MG in a positive way. Probably not, actually. But I do get some pretty okay tones out of mine. It still has the Marshall tonality, which in a way makes me respect Marshall. As a brand they have an awareness of what it is to sound like a Marshall, and for decades they've been making all kinds of stuff to achieve this. Dirt boxes, solid state practice amps, powerful tube heads, all get in that ballpark, even though their circuits are vastly different. That takes engineering AND ears. |
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| Author: | chris_d [ Fri Oct 09, 2015 7:29 am ] |
| Post subject: | Re: Marshall One Watt Series |
I feel like we have discussed these lil guys here befoe, but mayhap not. I am assuming these are just basically classic preamp circuits more or less, into a dual triode as a push/pull power section? What i have heard of that stuff, is that amps can sound pretty great for their lowatt-ness, but will still sound a tad wee and missing frequencies(lower midsy ones especially) compared to proper big power tube maps. They are still heaps and bounds better than a lot of the low-watt single ended designs that are everywhere in DIY-land though. These still act like amps, whereas, most single ended amps i have hoid, tend to be way too raw. It becomes a different thing, good for something, but not so much, IMO, for simulating a real larger amp. 12AT7 or AU7 as a push-pull output stage like these marshalls is IMO, much nicer. Personally, i would totally use one to replace my current bedroom amp setup. I had intedned to build one a few years back, but i haven't had as much building time/money as i would like these last couple. Though, it is worf noting, that 1-ish watt is still relatively fuckloud. And that these things will sound most amplike, through a proper 4x12 cab. |
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| Author: | Zozobra [ Fri Jan 08, 2016 11:03 am ] | |||||||||
| Post subject: | Re: Marshall One Watt Series | |||||||||
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| Author: | chris_d [ Sat Jan 09, 2016 12:09 pm ] |
| Post subject: | Re: Marshall One Watt Series |
I have been bouncing back and forth between whether i am next going to build a superhot marshall circuit(jose/fortin style) just as a standalone preamp, or whether i want to make a proper amp of it, like a 6v6 based medium watter. This might however be an even more useful solution for me. Really simplifies the power transformer situation if there is such a relatively tiny current draw. I might draw one out and see if it makes sense to do it. I definitely like the concept of it, and i have really liked the sound of the maps i have heard built this way... hmm. |
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| Author: | Zozobra [ Sat Jan 09, 2016 5:24 pm ] |
| Post subject: | Re: Marshall One Watt Series |
It is a cool little circuit. The 1/0.1W switch is a neat feature and easy to implement given the low power. For bigger volumes it should be easy to make a suitable low powered reactive dummy load to feed into a big power amp. More infos on the 1W designs here: http://ax84.com/bbs/dm.php?thread=460389 |
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| Author: | chris_d [ Sun Jan 10, 2016 1:58 pm ] | |||||||||
| Post subject: | Re: Marshall One Watt Series | |||||||||
That is very interesting for the JCM. Kind of confirms one of my theories for my own theoretical/potential build, regarding the use of a mosfet for the cathode follower. I wasn't sure how that would get along in this style circuit. I love it in my other AC30-ish build, but wasn't sure if it would play nice with a bit more clipping going on into it. Works great, is a relatively simple plug-in there, reduces the need for PT mA, allows for fewer tubes, really no downsides as far as i am concerned. Also, knowing what that JCM-1 sounds like sort of leans me towards using that style PI. I was going to go standard long tail just so as to retain as much of the original circuit as possible so it would be sure to "sound right", but sound-wise, there doesn't seem to be any detriment to the cathodyne here, and gaining a half a triode for gainstage use is lovely/ideal, similar to the benefits of a mosfet CF... Hmm, this might need to happen. 
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| Author: | Zozobra [ Mon Jan 11, 2016 7:02 am ] |
| Post subject: | Re: Marshall One Watt Series |
It is certainly something that I'd like to tinker with soon. The Dragonfly ECC99 mini amp uses an IRF820 as a source follower to drive the tone stack and that works pretty well. I'm going to have a good think about how to approach this. I have a mini toroidal PT from a preamp that is near ideal for this purpose. I say near. It will pump out about 320VDC which is a little too high for a 12AU7 poweramp so I would have to invoke some sort of voltage dropping scheme. I suppose a 5W series resistor will do in a push. It's not like it's pulling much current to cause sag. The other option is to use an ECC99 for about 2W of output. The PT doesn't quite have enough to run the heaters for an ECC99 and 2 12AX7s so I'll have to strap in a mini filament transformer to run the ECC99 heaters, which I can score for cheaps from my regular common garden components supplier. Many people regard the ECC99 as being the superior option for low power push pull so I am leaning that way. As for topography I am thinking of using the clean channel of the Laney Klipp as the preamp. I can either run it in the standard configuration of 2 stages/CF/TS and then hope the output from the TS is enough to drive a cathodyne well enough that it can push enough swing to the output or substitute the CF for a mosfet source follower and then use the freed up triode as a recovery stage after the TS. I think this one will have to be built on the bench to test both circuits before committing to a chassis as I ideally want to make this little beast as compact as possible. |
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| Author: | Zozobra [ Thu Jan 14, 2016 7:13 am ] |
| Post subject: | Re: Marshall One Watt Series |
Another interesting approach if you want to keep the triode as a CF for low to mid gain tones is to use a mosfet PI. I started a topic over at mef about low powered amps and they suggested trying this so fuck it, why not? It's not like we're relying on the PI for tone as by the time it gets close to distorting the grids of the 12AU7 will probably have melted  deets: http://music-electronics-forum.com/t41158/ |
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